Files

T

dimgigov 4a83eb6783 docs: update distributed/backup/schema/storage for multi-database

- Add multi-database limitations to distributed docs
- Fix backup commands and add multi-database backup guidance
- Add SQL migration section to schema docs
- Update storage examples to use per-database paths

2026-05-21 09:44:25 +03:00

2.6 KiB

Raw Blame History

Distributed Systems

BaraDB supports distributed deployment with Raft consensus, sharding, and replication.

⚠️ Multi-Database Limitation The distributed modules (Raft, sharding, and replication) are currently wired to the default database only. If you use multiple databases (CREATE DATABASE, USE DATABASE), distributed features do not yet span across them. Each database would need its own cluster setup.

Raft Consensus

Leader election and log replication:

import barabadb/core/raft

var cluster = newRaftCluster()
cluster.addNode("node1")
cluster.addNode("node2")
cluster.addNode("node3")

let n1 = cluster.nodes["n1"]
n1.becomeCandidate()
n1.becomeLeader()
let entry = n1.appendLog("SET key1 value1")

Sharding

Distribute data across nodes:

import barabadb/core/sharding

var router = newShardRouter(ShardConfig(
  numShards: 4,
  replicas: 2,
  strategy: ssHash
))
router.rebalance(@["node1", "node2", "node3"])
let shard = router.getShard("user_123")

Sharding Strategies

Strategy	Description
`ssHash`	Hash-based sharding
`ssRange`	Range-based sharding
`ssConsistent`	Consistent hashing

Replication

import barabadb/core/replication

var rm = newReplicationManager(rmSync)
rm.addReplica(newReplica("r1", "10.0.0.1", 9472))
rm.connectReplica("r1")
let lsn = rm.writeLsn(@[1'u8, 2, 3])
rm.ackLsn("r1", lsn)

Replication Modes

Mode	Description
`rmSync`	Synchronous replication
`rmAsync`	Asynchronous replication
`rmSemiSync`	Semi-synchronous replication

Gossip Protocol

Membership and failure detection:

import barabadb/core/gossip

var g = newGossipManager()
g.addNode("node1")
g.addNode("node2")
g.tick()  # Exchange membership info

Distributed Transactions

Two-phase commit across nodes:

import barabadb/core/disttxn

var dt = newDistributedTxn()
dt.prepare(@["node1", "node2"])
dt.commit()

Formal Verification

Core distributed algorithms are formally specified in TLA+ and model-checked:

Raft Consensus — formal-verification/raft.tla
- Verified: ElectionSafety, StateMachineSafety
Two-Phase Commit — formal-verification/twopc.tla
- Verified: Atomicity, NoOrphanBlocks
Replication — formal-verification/replication.tla
- Verified: MonotonicLsn, AcksRemovePending

Run TLC locally:

cd formal-verification
java -cp tla2tools.jar tlc2.TLC -config models/raft.cfg raft.tla
java -cp tla2tools.jar tlc2.TLC -config models/twopc.cfg twopc.tla
java -cp tla2tools.jar tlc2.TLC -config models/replication.cfg replication.tla

2.6 KiB Raw Blame History